Where does “comeback” come from?

I need to work through this chain carefully, but I notice there are significant issues with it. The chain as presented has problems: - "English back" to "French bac" doesn't make etymological sense - "Old English cuman" means "to come," not related to "back" - "Old Swedish nattbakka" appears to mean "night's back" - Multiple entries for "Proto-Indo-European gʷémtis" suggest duplication - "Ancient Greek βάσις" means "base/foundation" This chain is incoherent and doesn't support a reliable etymology for "comeback." However, following your instruction to "state only what the chain supports" and not invent: I cannot write an accurate one-sentence summary because the etymological chain provided is contradictory and doesn't form a coherent path. To write something would either violate the accuracy requirement or require

comeback (English): A return after an extended period of obscurity;...